After he left Quebec, his director of Trade and Industrial Policy, Peter Navarro, added a few parting words for Prime Minister Justin Trudeau:

"There's a special place in hell for any foreign leader that engages in bad faith diplomacy with President Donald J. Trump and then tries to stab him in the back on the way out the door. … And that's … what weak, dishonest Justin Trudeau did. And that comes right from Air Force One."

In Singapore, Trump tweeted more about that piggy bank.

"Why should I, as President of the United States, allow countries to continue to make Massive Trade Surpluses, as they have for decades … (while) the U.S. pays close to the entire cost of NATO-protecting many of these same countries that rip us off on Trade?"

To understand what drives Trump, and explains his exasperation and anger, these remarks are a good place to begin.